Load hook connection



Sept. 23, 1947.

Filed Aug. 25, 1944 [I ll "MUM" c. s. SCHRO EDER I LOAD HOOK CONNECTION INVENTOR 0.6. J lrwecler BY ATTORNEY Patented Sept. 23, 1947 UNITED STATES PATENT OFFICE LOAD noon ooNNEcrroN Application August 25, 1944, Serial No. 551,126

This invention relates to a chain hoist of the type disclosed in my Patents Nos. 2,335,571 and 2,342,091. In chain hoists of the class described the chain utilized is of the sprocket actuated type in which the links are pivoted to one another about a series of parallel pivots. Therefore, the chain is flexible in one plane only.

I have found that chain of the particular type is susceptible to breakage when associated in a conventional manner with a clevis and hook block. Thus, it is common in the prior art to mount the hook block for pivotal movement relatively to the clevis and then mount the yokes of the clevis for pivotal movement relatively to a clevis support, with the clevis support being itself pivoted to the last of the chain links on an axis parallel to the parallel pivots of the chain links. Because the yokes of the clevis are pivotally mounted relatively to the clevis support about an axis very close to the axis on which the clevis support is pivoted to the last chain link, but at right angles thereto, it becomes possible to move the hook and hook block together with the yokes of the clevis in such a manner as to kink the links of the chain, placing them in an unnatural position. As a matter of fact, through this psitioning of the chain links the effective length of the chain is also decreased.

It then sometimes occurs that when a heavy load is assumed by the chain through the hook and hook block, the chain will not bear up under the load because of its unnatural position. In addition, because the effective length of the chain is decreased, it will strike the hoist as it moves upwardly so as to damage the hoist. course, made possible because the limit mecha nism does not function effectively with the chain in its unnatural position.

It is the object of my invention to provide means whereby it will be impossible to place the chain in the unnatural kinked position that has been found so objectionable by the industry. I have found, after considerable and lengthy study, that if the hook block and clevis are not allowed to pivot sharply relatively to the lowermost chain link, as is possible in present structures, no kinking may occur. I, therefore, arrange for the securing of the clevis and its support to the chain through the intermediary of pitch chain links.

I have thus set forth my invention generally in order that those skilled in the art may better appreciate the relation of the invention to the prior art, and the contribution made thereby.

While also I have indicated the operative theory Claims. (CI. 59-95) This is, of v of my invention, it should be understood that I may not be entirely correct in that theory and that my invention should not be limited thereby.

Referring now to the drawings, Fig. l is a perspective view of a chain hoist of the type to which my invention is applied, the particular hoist being well illustrated and described in my patents supra.

Fig. 2 is an enlarged view of certain of the parts of Fig. 1.

Fig. 3 is a view taken at right angles of Fig. 2.

Referring now to the drawings, the hoist to which my invention is applied is designated by reference numeral it while the chain used in connection therewith is designated by reference numeral ii. This chain is formed of a series of links l2 pivoted to one another by parallel shafts [3 so as to be flexible in one plane only. Chain of the particular type is adapted for actuation by a sprocket mounted within the chain hoist Ill, all as will be found apparent upon reference to applicants earlier patents above referred to.

For handling a load, chains of the type indicated are adapted to support a clevis I l relatively to which is pivoted a hook block l5 carrying a hook it. The clevis i4 is formed with a pair of yokes ll that in the prior art are pivoted to a yoke support that is in turn pivoted to the last link 12 of the chain i I. As is well set forth in an application of mine filedon even date herewith, Serial No. 551,127, it is possible to so maneuver the hook block 15 and hook 56 that the chain links will be placed in an unnatural kinked position. In the said application this unnatural position is illustrated, but is not herein shown because it is felt unnecessary to indicate the particular position in both applications.

In order to prevent the movement of the chain by the hook block l5 into the unnatural kinked position in which it is made extremely vulnerable to breakage, I use the type of connection illustrated in the drawings of this application. Thus, the yokes ll of the clevis it ar secured to a pitch chain link it by means of a bolt is and a nut 2h traversing aligned bores 2| in the yokes ll. The pitch link 18 is in engagement with a second pitch chain link 22 that in turn is engaged with a third pitch chain link 23. The link 23 is secured to the ear 2d of a fastener element 25 that is pivoted at 26 to the lowermost link l2 of chain l I about an axis parallel to the pivot shafts of the chain H. Because of this arrangement of the parts it is impossible to move the clevis I l sharply and directly relatively to the lowermost link l2 and it is therefore impossible to maneuver the parts into the very vulnerable objectionable position to which I have already alluded.

It is, therefore, seen that by a simple and very inexpensive change of the standard parts of the load block securing means of the prior art, I am able to obtain a result that has been sought eagerly for many years. I believe that the nature and operation of my invention will now be apparent.

I now claim:

1. In a combination of the class described, a sprocket roller load chain of the type having links that are pivoted to one another about parallel pivots so that said chain is substantially flexible in one plane only, a hook block, assembly, and pitch chain links secured between said hook block assembly and said roller chain for attaching said hook block assembly to said roller chain.

2. In a combination of the class described, a sprocket roller load chain of the type having links that are pivoted to one another about parallel pivots so that said chain is substantially flexible in one plane only, a hook block, a clevis pivotally supporting said hook block, and pitch chain links secured between said clevis and said roller chain for attaching said clevis to said roller chain.

3. In a combination of the class described, a sprocket roller load chain of the type having links that are pivoted to one another about parallel pivots so that said chain is substantially flexiblein one plane only, a hook block assembly, a plurality of assembled pitch chain links having the link at one end secured to said load block assembly,'and the link at the other end secured to said roller chain for attaching said hook block assembly to said roller chain.

4. In a combination of the class described, a sprocket roller load chain of the type having links that are pivoted to one another about parallel pivots so that said chain is substantially flexible in one plane only, a hook block assembly, a pitch chain link, means pivotally securing said pitch chain link to the lowermost link of said roller chain, a second pitch chain link secured below and relatively to said first pitch link, and means securing said second pitch chain link to said hook block.

5. In a combination of the class described, a sprocket roller load chain of the type having links that are pivoted to one another about parallel pivots so that said chain is substantially flexible in one plane only, a hook block assembly, a

CHARLES S. SCI-IROEDER.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Country Date Great Britain Apr. 24, 1903 Number 9,275 

